This invention relates to a contact printer for printing photographic negatives onto a photographic paper and to a method of contact printing.
A common process in the photographic field requires that a series of negatives arranged in rows and columns are printed onto photographic paper for viewing of initial proofs by which a selection can be made of those negatives to be printed to fine quality. The contact printing is often done in an apparatus dedicated for this purpose which includes a base plate or surface onto which the photographic paper can be placed underneath a container receiving the negatives in rows and columns following a transparent glass sheet is placed on top of the negatives covering the photographic paper. The photographic paper is then exposed by directing light through the transparent sheet and the negatives onto the paper.
One significant problem arises in the contact printing process which is that of effecting proper alignment between the container of negatives and the paper to ensure that the negatives are properly placed in a centralized position on the paper. Of course this alignment of the container of negatives and the paper must be effected in partial or complete darkness in the dark room and must remain in proper alignment when the transparent cover sheet is moved into position to compress the paper and the negatives together. It is of course necessary to initially locate the contact printer in the darkness and then to operate the contact printer to effect the required alignment. This operation has proven to be of significant difficulty to the average photographer leading to unsatisfactory results. In some cases the photographer uses oversize paper to ensure that all of the negatives are properly printed onto the paper. The use of oversize paper of course increases chemical and paper cost.
One particular apparatus of this general type includes a molded plastics base on which is provided a foam layer covering the whole of the base. The base includes upturned side edges rising to a height above the foam and a hinge arrangement at a top edge to which is attached an edge of the transparent glass sheet allowing the glass sheet to pivot from an initial raised position downwardly to horizontal position overlying the foam. The size of the base plate and the foam is oversized relative to the paper and to the container of negatives. In use the paper is laid on the foam with the photographic emulsion side upward and the container of negatives is located on top of the paper and moved by touch so that side edges of the container of negatives are, as far as possible, aligned with the side edges of the paper. The glass sheet is then pivoted into the closed position while (hopefully) the paper and the negatives remain aligned. The exposure is then completed and the cover panel opened to release the exposed photographic paper for chemical development. This device while widely used is generally unsatisfactory due to these difficulties of effecting the proper alignment in the darkness generally by touch alone.
The negatives are often contained in what is known as an "archival preserver" which comprises a plastic sleeve formed from top and bottom layers directly overlying to form a flat sleeve. The top and bottom layers are then heat sealed together by transverse lines spaced by the width of the negative so that the negatives can be inserted longitudinally of the receptacles so formed to define rows and columns of the negatives. The archival preserver sleeves often include an identification strip across the top edge allowing written information to be applied. The sleeves further include at least two generally three holes along one side edge allowing the sleeves to be placed in a conventional ring binder for storage.
With the negatives stored in this sleeve, the contact printing process is utilized as stated above to effect the printing of the negatives onto the paper with the paper having dimensions to closely match the outside dimensions of the rows and columns of negatives so that the paper is generally smaller than the size of the sleeve itself.